JP5988507B2 - Especially pressure sensitive adhesive tape for pasting windows of mobile devices - Google Patents

Description

  The present invention relates to a double-sided adhesive tape for affixing a window unit of a household electronic device and a polymer composition for producing a pressure-sensitive adhesive for such an adhesive tape.

  Nearly all devices of modern entertainment electronic devices are equipped with a visual display system for displaying the operating status of the device or other information. In this case, when a relatively complicated context is to be displayed, a display module based on a liquid crystal (LCD) or an organic light emitting diode (OLED) is often used for the display. Such a display is used in, for example, a digital camera, a portable micro computer, and a mobile phone.

  Such a display system covers the outer surface of the display module to reduce the risk of direct action on the module in order to protect the display module from damage that may be caused by external mechanical action such as impact, for example. It is common to provide a transparent protective window. Such protection is also necessary in the case of non-electronic visual display systems, for example in the case of mechanical indications such as watches or storage container residual quantity indications.

  The protective window is typically a polymer panel or glass panel (e.g. consisting of polycarbonate (PC), polymethyl methacrylate (PMMA)), each of which has advantages and disadvantages and is therefore specific. Must be selected according to the specific application.

  That is, polymer panels are inexpensive and easy to process and provide efficient protection against mechanical action, but are generally not scratch proof and therefore have the disadvantage of being easily damaged. This not only deteriorates the aesthetic impression of the display system in a short period of time, but also reduces the viewable range of the display area of the display module. In addition, many commercially available polymers have limited resistance to ultraviolet light (UV light) or organic solvents.

  On the other hand, the protective window made of glass is inert to organic solvents and is also scratch proof because of its high hardness, thus giving a high value impression. However, because of the fragility of this material caused by its hardness, glass is only limitedly suitable for protection against mechanical actions such as impact or impact. This is because the glass panel can already cause brittle fracture under a weak load. Therefore, not only is the protective action limited, but there is also a risk of injury due to the fragments that occur and the risk of damage to the display module due to sharp edges.

  Fixing display protection windows in electronic devices, especially portable small devices such as mobile phones and the like, usually in housings made of plastic or metal, is mainly done by double-sided adhesive tape today. In that case, in order to always adapt the double-sided pressure-sensitive adhesive tape to the material to be applied, that is, to apply the glass, in general, an adhesive tape that exhibits a certain degree of shock absorbing behavior, that is, can reduce mechanical shock. When using plastic (polymer panel) on the other hand, it is important to compensate for bending stress.

  The interest in the manufacture of such small electronic devices is that, for reasons of practicality and cost, only one type of adhesive tape can be used that can also have advantageous properties derived from various materials that have been used so far. is there.

Test Methods for Pressure Sensitive Adhesive Tapes, 15th edition, published by Pressure Sensitive Tape Council, Northbrook (Illinois), USA

  Accordingly, those skilled in the art are provided with adhesive tapes that are suitable for glass or transparent plastics for household electronic products, and at the same time contribute to protecting these products from external influences. The objective task was to do. In particular, it is advantageous that a bending stress compensation and an excellent shock absorption are realized. Since some mobile devices are exposed to temperature fluctuations and relatively high temperatures, it is further preferred that the adhesive tape has a cohesive persistence at high temperatures.

Surprisingly, it has been confirmed that an adhesive tape based on an acrylate polymer exhibits a desired suitability when a specific cross-linked state is realized and the resin ratio is limited. Thus the subject claim 1 is a double-sided pressure sensitive adhesive tape comprising a pressure sensitive adhesive layer on the one support layer and two outer, at least one of a pressure sensitive adhesive both pressure sensitive adhesive layer of the Is a cross-linked product, which consists of a polymer composition comprising at least the following components: A) a polymer component (component A),
A polymer component comprising 88-100% by weight of at least one polyacrylate (component A1) consisting of a), b)
a) 1 to 15% by weight relative to component A1,
One or more monomers having at least one ethylenically unsaturated bond, each selected so that the glass transition temperature _TG of the corresponding homopolymer of each monomer is at least 0 ° C. (Monomer a),
However, at least a part of the monomer (a) further has at least one carboxylic acid group (monomer a1),
b) 85 to 99% by weight relative to component (A1),
One or more monomers from the group of acrylic esters and methacrylic esters, each selected so that the glass transition temperature _TG of the corresponding homopolymer comprising each monomer is -30 ° C or lower. Monomer (monomer b),
B) consisting of a polymer composition comprising at least one crosslinking agent (component B) having two or more functional groups that are covalently crosslinked,
The at least one cross-linking agent has an amount ratio V = n _Z / n _P of 0.15 of the amount n _Z of the cross-linking active center of the cross-linking agent and the theoretical amount n _P of the macromolecule of the polymer component A1. is present in an amount showing a value between 0.60, amount of substance n _Z of the crosslinking active centers of the crosslinker, the crosslinker weight multiplied by the number f of the crosslinking active centers per crosslinker molecule m _V calculated by dividing the a molar mass M _V of the crosslinker, i.e., _{n Z = f · m V /} M V, amount of substance n _P theoretical macromolecular polymer component A1 during pressure-sensitive adhesive It relates to an adhesive tape obtained by dividing the mass m _P of the polymer component by the number average molar mass M _{n, P} of this component, that is, n _P = m _P / M _{n, P.}

  The subject of the present invention is also an advantageous form of such an adhesive tape and the use of the corresponding adhesive tape for affixing components of consumer electronics products, in particular display windows of such products It is.

  Finally, the invention relates to a polymer composition for producing a pressure sensitive adhesive for the adhesive tape according to the invention. All embodiments of the cross-linked pressure sensitive adhesive herein, especially the components and their composition, apply accordingly to the uncross-linked polymer composition. The same is true for the reverse.

  The pressure sensitive adhesive for the adhesive tape according to the invention is a crosslinked product consisting of a polymer composition comprising at least one polymer component A and a crosslinking agent B. In the simplest realization of the present invention, the pressure sensitive adhesive is limited to a cross-linked product of only both of these components (so that component A and component B together make up 100% of the polymer composition before cross-linking). . The usual small percentage, for example up to 3% by weight of contaminants, does not significantly affect the achievement of the desired properties and is therefore indicated as 100% by weight. However, it is desirable to reduce contaminants as widely as possible (eg, to less than 1% by weight) and most preferably to eliminate them.

  Contaminants here and below are those compounds which are unintentionally carried into the respective system (for example together with added monomers) and which do not fall within the definition of the ingredients which are intentionally supplied. That is.

  By fine-tuning between the amount of cross-linking agent, the polyacrylate component A1 and the maximum resin amount adapted to it, the pressure-sensitive adhesive can add further component C not included in the definition of component A and component B. It is desirable to include up to 5% by weight, preferably up to 3% by weight, so that component A and component B together are at least 95% by weight of the polymer composition for making a crosslinked pressure sensitive adhesive, and better Is at least 97% by weight.

  Pressure sensitive adhesives, if desired in individual cases, include additives such as softeners (plasticizers) (component C), filler materials (eg fibers, carbon black, zinc oxide, titanium dioxide, chalk, solid Glass spheres or hollow glass spheres, microspheres made of other materials, silicic acid, silicates), nucleating agents, foaming agents, compounding agents and / or forms of eg primary and secondary antioxidants Alternatively, an anti-aging agent in the form of a light stabilizer can be added. However, pressure sensitive adhesives are already fine-tuned without additives for the desired properties, so it is advantageous for the present invention to have each of these additives, any combination, or none at all. is there. In particular, the proportion of additives optionally added to the adhesive should not exceed 5% by weight, preferably 3% by weight.

  The further resin corresponding to component A2 is not considered an additive in the above sense.

  The following embodiments apply to pressure sensitive adhesives based on both component A and component B alone, as well as further developments or variations.

Properties of pressure-sensitive adhesive tape and its underlying pressure-sensitive adhesive To achieve excellent pressure-sensitive adhesive properties for cross-linked polymers, the quantitative composition of the components used is appropriate for the polymer using the Fox equation It is advantageous to select such that a stable glass transition point _TG occurs.

  The pressure sensitive adhesive tape according to the invention can be particularly well characterized by the determination of the viscoelastic properties of the pressure sensitive adhesive by rheological tests.

For example, when applying a sinusoidal load to a sample, as in the case of dynamic mechanical analysis (DMA), the characteristic characteristic resulting from the viscoelasticity of the sample is that the frequency of the sine function, ie the respective load stage, It depends on the time of action, on the other hand on the temperature. In doing so, both influence variables interact. Thus, with respect to the glass transition point, that is, the state in which the polymer material exhibits the greatest change in deformability (transition from a glassy fragile region to a soft entropic elastic region), a constant frequency and a continuous linear temperature change ( A characteristic glass transition temperature _TG can be found during the loading action at temperature sweep) and a characteristic glass at the loading action at a constant temperature and continuous frequency change (frequency sweep). it is possible to determine the transition frequency f _G. In practice, the so-called time-temperature superposition method (TTS) can be applied particularly well to the determination of the glass transition frequency f _G , in which case frequency measurements carried out at regular temperature intervals are transferred to a frequency sweep. Thus, it is possible to extend several tens of times below and above the range obtainable by measurement.

  For the pressure sensitive adhesive used in the pressure sensitive adhesive tape according to the present invention, the glass transition temperature (dynamic measurement at 10 rad / s, DMA, see below) is -11 ° C or lower, preferably -15 ° C or lower. It is advantageous to be.

  For the excellent resilience characteristics of a pressure sensitive adhesive, it is advantageous if the pressure sensitive adhesive can disperse energy well. This is advantageously indicated by the preferred loss factor tan δ (ratio of loss modulus G ″ to storage modulus G ′), which is here a viscoelastic system such as a pressure sensitive adhesive. The loss modulus G ″ represents a viscous characteristic, that is, the viscoelasticity of this system can be characterized by only one material characteristic value. These values can be obtained, for example, by dynamic mechanical analysis (DMA) (see below, chapter “Measurement methods”). The data for the loss factor tan δ (as well as the loss modulus G ″ and the storage modulus G ′) relate to this measurement unless otherwise indicated in the individual case.

  The loss factor tan δ at 0.1 rad / s and 85 ° C. is in the range of 0.35 to 0.75, preferably in the range of 0.40 to 0.65, particularly preferably in the range of 0.41 to 0.60. It is very advantageous to be within range.

Shock absorption, it was confirmed that the characterized by glass transition frequency f _G. In order to achieve the desired properties of the pressure-sensitive adhesive tape according to the invention, in particular shock absorption, the glass transition frequency at 25 ° C. (see below for data, chapter “Measurement”) is above 5000 rad / s. The case is very advantageous. In particular, it has been found that pressure sensitive adhesives having a glass transition frequency higher than this boundary value have the ability to disperse impact energy from short and strong impact action, as is the case, for example, in the event of a crash due to falling.

  The so-called “rolling ball tack” measurement also showed that it was possible to inductively estimate the shock absorption capacity. This test is usually used to characterize the initial adhesion of a pressure sensitive adhesive. In general, an excellent impact absorbing ability was confirmed for a sample that resulted in a rolling ball test of less than 50 mm.

Component A1 / Polyacrylate Polymer component A itself comprises 88% by weight, preferably 90% by weight or more, up to 100% by weight of one or more polyacrylates (component A1). That is, the polymer component A can consist only of the polyacrylate component A1, but optionally one or more further components can be present up to 10% by weight. This further component can be, for example, in whole or in part, the resin component (component A2) (see below). Therefore, the polymer component A can be composed of only the polyacrylate component A1 and the resin component A2, provided that, even when the resin component A2 is present, the polymer component A is not limited to the polyacrylate component A1 but one or more further components Components (A3, A4 ...) can be included.

  Again, the usual small percentage, for example up to 3% by weight of contaminants, does not significantly affect the achievement of the desired properties and is therefore indicated as 100% by weight. However, it is desirable to reduce contaminants as widely as possible (eg, to less than 1% by weight) and most preferably to eliminate them.

The polyacrylate component A1 itself includes the following a) and b) according to the present invention.
a) 1% by weight relative to component A1, preferably 3% by weight, up to 15% by weight,
One or more monomers having at least one ethylenically unsaturated bond, each selected so that the glass transition temperature _TG of the corresponding homopolymer of each monomer is at least 0 ° C. (Monomer a),
In this case, at least a part of the monomer (a) further has at least one carboxylic acid group (monomer a1),
b) 85% to 99% by weight, preferably up to 97% by weight, relative to component (A1),
One or more monomers from the group of acrylic esters and methacrylic esters, each selected so that the glass transition temperature _TG of the corresponding homopolymer comprising each monomer is -30 ° C or lower. Monomer (monomer b).

The glass transition temperature _TG data relate to determination by dynamic mechanical analysis (DMA) at low frequencies (see below, chapter “Measurement”), unless otherwise indicated in each case.

  Advantageously, component a and component b together make up 100% of the polyacrylate component A1, that is, the polyacrylate component A is composed solely of these components. Again, the usual small percentage, for example up to 3% by weight of contaminants, does not significantly affect the achievement of the desired properties and is therefore indicated as 100% by weight. However, it is desirable to reduce contaminants as widely as possible (eg, to less than 1% by weight) and most preferably to eliminate them.

  However, Component a1 and Component b can be added in a proportion of less than 100% by weight. In that case, the polyacrylate component A comprises one or more additional components c, d,. . . (Comonomer c, d, ...) together (up to 100% by weight of polyacrylate component A1) up to a weight fraction of up to 12% by weight, preferably up to 10% by weight.

  Comonomers c, d,. . . Can be used the usual comonomers known to the person skilled in the art for polyacrylates.

  It is very advantageous that the proportion of monomer a1 in the polyacrylate component A1, ie the proportion of monomers having at least one carboxylic acid group, is 3 to 5% by weight (relative to the polyacrylate component A1). When the proportion of the carboxylic acid group-containing monomer is at least 3% by weight, the reactivity of the added crosslinking agent is significantly improved, resulting in an excellent reaction rate of the crosslinking process.

Monomers in the sense of component a1 having at least one ethylenically unsaturated bond, the glass transition temperature _TG of the corresponding homopolymer being at least 0 ° C. and selected to have at least one carboxyl group Is preferably selected from the group comprising acrylic acid and / or methacrylic acid, particularly preferably acrylic acid.

Component A1 can contain only monomers of type a1 as monomer a, but component a may consist of partial type a1 monomers and partial further comonomers ai, each of which is The glass transition temperature _TG of the corresponding homopolymer consisting of each monomer is selected to be at least 0 ° C., but without carboxylic acid groups.

In the meaning of the comonomer ai, it is possible in particular to use the monomer a2 in whole or in part, which monomer a2 is selected from the group of compounds having at least one ethylenically unsaturated bond, and each monomer the glass transition temperature _TG of the corresponding homopolymer consisting of a2 is selected to be at least 0 ° C., and the monomer a2 has at least one ester group having an ethyl residue and / or a methyl residue ing. This is in particular acrylic esters and / or methacrylic esters, so group a2 in this case comprises acrylic acid methyl esters, acrylic acid ethyl esters, methacrylic acid methyl esters, and methacrylic acid ethyl esters. Monomer a2 can affect the polarity of the pressure sensitive adhesive. For planned applications, it is suitable for applying materials that are more or less polar per se, such as glass, polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polycarbonate (PC), and the like. The advantage of being granted arises. To improve adhesion to such a foundation, when using polar comonomers such as the aforementioned compound classes that can improve the adhesion of the adhesive to the foundation by van der Waals forces and / or dipolar interactions Can be advantageous. However, if the component a2 is used in a very large amount, the impact absorbing ability of the adhesive is generally impaired. This is because polar monomers usually have a high glass transition temperature of the corresponding homopolymer, so that the pressure sensitive adhesive becomes too hard and too brittle. Therefore, it is advantageous to use up to 10% by weight of monomer a2 as comonomer.

  Component A1 can only contain monomers of type a1 and type a2 as monomer a, but component a consists of a partial type a1 monomer, a partial type a2 monomer, and a partial type a3 monomer. It may be composed of further comonomers, which belong to the definition of monomer a but do not belong to the definitions of type a1 and type a2. Type a3 comonomers carry neither carboxylic acid groups nor ester groups with ethyl and / or methyl residues. Component A1 can also contain only monomers of type a1 and type a3 as monomer a.

  Monomers of type a3 can be particularly useful for adjusting the glass transition temperature and / or glass transition frequency of the resulting pressure sensitive adhesive towards the final desired value.

For example, the following monomers can be used as the monomer a3. That is, benzyl acrylate, benzyl methacrylate, phenyl acrylate, phenyl methacrylate, isobornyl acrylate, isobornyl methacrylate, t-butylphenyl acrylate, t-butylphenyl methacrylate, cyclohexyl methacrylate, 3,3,5-trimethylcyclohexyl acrylate, 4- Biphenyl acrylate, 4-biphenyl methacrylate, 2-naphthyl acrylate, 2-naphthyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, dimethylaminopropyl acrylamide, dimethylaminopropyl methacrylamide, and N, N-dialkyl substituted amides such as N, N -Dimethylacrylamide, acrylonitrile, vinyl methyl ether, Chill vinyl ether, such as vinyl isobutyl ether, vinyl esters, styrene, alpha-and p- methylstyrene, 2-polystyrene methacrylate (molecular weight _M W _4000~13000g / mol), poly (methyl methacrylate) ethyl methacrylate _{(M W} Macromonomers such as 2000-8000 g / mol).

  In particular, when component a1 is in a proportion of 3 to 5% by weight in component A1, component a2, component a3, or the sum of components a2 and a3 is up to 12% by weight in component A1, in particular up to 10% by weight. This is advantageous.

The polyacrylate component A1 further comprises 85 to 99% by weight of one or more monomers b, and the monomers b are such that the glass transition temperature _TG of the corresponding homopolymer comprising each monomer b is -30 ° C. or less. And selected from the group of acrylic esters and methacrylic esters.

  As a monomer in the meaning of component b, for example, an acrylate ester can be used in whole or in part, especially in combination with the monomers described below, in which the alkyl group is linear and at least It has 3 C atoms, preferably up to 14 C atoms. Particular preference is given to using acrylic esters having linear alkyl residues with 4 to 9 carbon atoms. For the aforementioned monomers, it is preferred to use unsubstituted acrylate esters. Examples of this monomer are propyl acrylate, n-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, n-heptyl acrylate, n-octyl acrylate, n-nonyl acrylate, n-decyl acrylate, n-undecyl. Acrylate, n-dodecyl acrylate, n-tridecyl acrylate, and n-tetradecyl acrylate.

  Furthermore, regarding the component b, if the glass transition temperature condition is satisfied, an acrylate ester having a branched hydrocarbon residue and / or a hydrocarbon residue substituted with a functional group, alone or as a comonomer Can be used. With regard to these monomers, there are some other monomers that can be advantageously used as examples. 2-Heptyl acrylate, 2-octyl acrylate, 2-ethoxyethyl acrylate, 2-ethylhexyl acrylate, 2-ethylbutyl Acrylate, 3-methoxybutyl acrylate, 2-methoxyethyl acrylate, 3-methoxypropyl acrylate, 3-methylbutyl acrylate, and isodecyl acrylate.

Many methacrylic esters can also be used successfully in the sense of component b), but again _TG conditions must be noted. Examples of such monomers are octadecyl methacrylate, decyl methacrylate, dodecyl methacrylate.

  The aforementioned and further monomers having a glass transition temperature of −30 ° C. or less can each be used alone or in combination with one or more further such monomers. And, for example, the combination of n-butyl acrylate and ethyl hexyl acrylate is an excellent monomer mixture for component b.

Production of the polyacrylate component A1 The polyacrylate component A1 can be produced by polymerization of the aforementioned components, in particular by radical polymerization, by conventional methods known to those skilled in the art. The polymerization is preferably operated so that the resulting polymer has a number average molecular weight M _n of at least 50,000 g / mol. The number average molecular weight M _n preferably does not exceed a value of 250,000 g / mol. Particularly preferred is that the number average molecular weight M _{n of the} polyacrylate component A1 is in a range between 50,000 g / mol and 150,000 g / mol. All data on the molecular weight of the polymer relate to the measurement by gel permeation chromatography (see below, chapter “Measurement”).

Component A2 / resin Optionally, the polymer component A can comprise up to 12%, preferably up to 10% by weight of a resin component comprising one or more resins (component A2). The resin in the meaning of the present specification means an oligomer compound and a polymer compound having a number average molecular weight M _n of 5,000 g / mol or less (gel permeation chromatography, see below). In particular, the main part of the resin (with respect to parts by weight of the entire resin component) has a softening point of 80-150 ° C., preferably all resins have a softening point of 80-150 ° C. Data for softening point T _E of polymeric compounds, unless anything presented to others in individual cases, DIN EN 1427: on the values determined by the ring and ball method based on 2007 (see below, chapter "Measurement method" ).

  It is desirable that the resin proportion in the polymer component does not exceed 12% by weight. This is because such a high resin ratio has an adverse effect on the impact absorption characteristics. Preference is given to the resin proportion not exceeding 10% by weight.

  In the meaning of the resin component A2, a natural resin and / or a synthetic resin can be used. In principle, any resin whose softening point is within the aforementioned temperature range can be used. Suitable adhesive resins include rosin and rosin derivatives (rosin esters, rosin derivatives stabilized by, for example, disproportionation or hydrogenation), polyterpene resins, terpene phenol resins, alkylphenols, to name a few. Resins, aliphatic, aromatic and aliphatic aromatic hydrocarbon resins. It is highly preferred to select a resin that is compatible with the polyacrylate component (dissolvable in the polyacrylate component or homogeneously mixed with the polyacrylate component).

  Advantageously, a mixture of resin components can be used to adjust the glass transition range of the pressure sensitive adhesive (as a whole). Furthermore, the mixing of one or more resins often contributes to a better dispersion of energy, so that the resin mixing can be used to fine tune the loss factor.

Component B / Crosslinking agent In order to crosslink the pressure sensitive adhesive , a specified amount of a crosslinking agent (Component B) having at least one kind of two or more functional groups is added to the polyacrylate system to be crosslinked. . The cross-linking agent can constitute the linking site via the carboxylic acid group of the polyacrylate (introduced by component a1).

  According to the present invention, one (or more) crosslinker is added in an amount such that the ratio V is in the range of 0.15 to 0.60. Preferably the value V is 0.2 or more, especially in the range of 0.22 to 0.58.

A plurality of cross-linking agents can also be used according to the present invention. When using multiple crosslinkers, especially when using multiple crosslinkers of different functionality, the definition of the ratio V presented in claim 1 must be applied, ie V = n _Z / n _P , In the formula, n _Z is the total amount of the crosslinking active center of all the crosslinking agents, that is, n _Z = f ₁ · mV _{, 1} / MV _{, 1} + f ₂ · MV _{, 2} / MV _{, 2} . . .
In the above formula, subscript 1 means the first crosslinker value, 2 means the second crosslinker value, and so on.

By knowing the number average molecular weight (GPC) of the polymer sample, the amount of crosslinking agent to be added based on the main claim can be easily determined if the average molecular weight of the crosslinking agent and the functionality of the crosslinking agent are known. If only one crosslinking agent is not present, the cross-linking agent, advantageously used, quantitative m _V apply to define a corresponding value is introduced, the number average of quantitation m _P and polymer components of the polymer components by the following equation It can be seen from the molar mass M _{n, P} (M _V = molecular weight of the crosslinker).

  If there are several cross-linking agents, in particular several cross-linking agents of different functionality, this formula must be adapted accordingly.

  For cross-linked pressure sensitive adhesives, the cross-linking density corresponding to an average cross-linking site of 0.15 to 0.60 per macromolecule of polymer component is particularly high when the cross-linking reaction is carried out to a nearly complete reaction. Approximate well.

  The one or more crosslinking agents are crosslinking agents that can be covalently crosslinked and react with carboxyl groups. In order to ensure sufficient temperature resistance, it is particularly advantageous to select a chemically bonded (covalently crosslinked) system as the crosslinker component (crosslinkers that are not chemically bonded, for example chelating crosslinkers). For adhesives cross-linked with, the linking site reopens at high temperatures, thus the system will lose its cohesive properties). This means that the cross-linking agent is in particular a cross-linking agent capable of covalently bonding to the polyacrylate macromolecule via the carboxylic acid group, and can create one linking site for each functionality of the cross-linking agent molecule [and thus Bifunctional crosslinkers can connect two macromolecules to each other through two linking sites, and trifunctional crosslinkers connect three macromolecules through three linking sites (each for each macromolecule). Via one carboxylic acid group) or two macromolecules via three linking sites (by one carboxylic acid group of one macromolecule and two carboxylic acid groups of a second macromolecule, etc.). It has proved to be very advantageous if, on average, a crosslink density corresponding to 0.15 to 0.6, in particular 0.22 to 0.58 crosslink sites per macromolecule of the polymer component is achieved. In this connection, it is particularly advantageous if the crosslinking reaction is carried out as close as possible to the complete reaction (preferably> 90%, more preferably> 95%). By advantageously realizing the degree of crosslinking, the cohesiveness of the cross-linked adhesive is sufficiently high so that the adhesive does not crack under bending loads, but the cohesiveness does not cause adhesion failure of the adhesive under bending loads. It is also low enough that it does not occur (avoid cross-linking by appropriately selecting the number of cross-linking sites).

  The cross-linking agent (s) is advantageously selected such that it does not react significantly with the hydroxy functionality and / or especially water under normal storage conditions to which uncross-linked pressure sensitive adhesives are often exposed. It is. This avoids a reduction in reactivity due to such reactions, which is often the case when using crosslinkers such as isocyanates.

  Very suitable crosslinking agents are those having 3 or 4 functional groups per molecule of crosslinking agent (trifunctional and tetrafunctional crosslinking agents). It has been found that crosslinkers that are particularly suitable and that are also well storable are compounds carrying both epoxy and amine groups. Such a particularly well-suited crosslinker has, for example, at least one amine group and at least two epoxy groups in the molecule, and a much more effective crosslinker has, for example, two amine groups and four Has an epoxy group. N, N, N ', N'-tetraglycidylmetaxylenediamine (CAS No. 63738-22-7) has been found to be a particularly well-suited crosslinking agent. Also very well suited is 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane (CAS No. 65992-66-7). This crosslinker with epoxy and amine groups in the molecule is characterized by a long crosslinker solution invariance (processable time, “pot life”) and exhibits reduced reactivity due to reaction with water. Nevertheless, it is characterized by a high crosslinking rate. Furthermore, with such crosslinking agents, a defined degree of crosslinking within the target range of the present specification can be achieved without causing significant postcrosslinking during storage of the crosslinked product.

  In addition to the selected cross-linking agent that covalently cross-links to ensure the best possible cross-linking, there may be no additional cross-linking agents (such as chelate cross-linking agents) that react by another cross-linking mechanism. It is advantageous.

Summary of pressure-sensitive adhesive components (to make it easier to see)
Component A: Polymer Component Component B: Crosslinking agent (having two or more functional groups )
Component A1: Polyacrylate component, Partial component of component A Component A2: Resin component, Optional partial component of component A A3, A4,. . . An optional partial component a of component A (consisting of monomer a): a partial component of polyacrylate component A1 [monomers having at least one ethylenically unsaturated bond, each corresponding to a respective monomer Monomers selected so that the glass transition temperature _TG of the homopolymer is at least 0 ° C.]
Component b (comprising monomer b): partial component of component A1 [(meth) acrylic selected such that the glass transition temperature _TG of the corresponding homopolymer of each monomer, respectively, is at most −30 ° C. Acid ester]
Components c, d,. . . : Optional partial component of component A1 component a1 (consisting of monomer a1): partial component of component a [having one or more carboxylic acid groups]
Component a2 (consisting of monomer a2): optional subcomponent of component a [having at least one ester group with an ethyl residue and / or a methyl residue]
Component a3 (consisting of monomer a3): optional partial component of component a [no carboxylic acid group, no ester group with ethyl or methyl residues]
In the above list, the concept of “partial component” does not exclude 100% of these components in terms of language.

Support film As support material for the adhesive tape according to the invention, it is advantageous to use plastic films, particularly preferably films made of PET (polyethylene terephthalate). The layer thickness of the support film is preferably 4 to 50 μm. In order to facilitate the shaping of flat molded parts (sections or cuts of adhesive tapes, so-called “die cuts”), in particular die-cutting, or for the first time depending on the nature of the pressure-sensitive adhesive (cohesiveness) The support film serves especially as a stabilizing film for the adhesive tape. Furthermore, the film makes it easier and better to remove the applied adhesive tape from the base (removability).

Structure of the adhesive tape The pressure-sensitive adhesive tape according to the present invention particularly preferably has a thickness in the range of 100 to 300 μm. In this regard, the support film can be placed symmetrically or asymmetrically between the pressure sensitive adhesive layers (FIG. 1 shows a symmetrical tape, where 1.1 and 1.2 = pressure sensitive adhesive 1.3 = support film, Figure 2 shows an asymmetric tape, where 2.1 and 2.2 are pressure sensitive adhesive layers, 2.3 shows a support film) . It is preferable to use a support film having a thickness in the range of 4 to 50 μm. It is advantageous if the thickness of the support is selected to be 20% or less, in particular 10% or less, of the total thickness of the pressure-sensitive adhesive tape, so that the proportion of the support in the thickness of the adhesive tape is The desired properties of the adhesive tape derived from the pressure sensitive adhesive can be exerted without becoming too high.

  It is advantageous if the pressure sensitive adhesive tape has a geometrically symmetrical structure, i.e. the pressure sensitive adhesive layer is formed on both sides of the support film with the same thickness.

  Especially in combination with geometric symmetry, when the pressure sensitive adhesive on both sides of the adhesive tape according to the invention is chemically identical, that is, a pressure sensitive adhesive as shown in the basic form or variations thereof is shown. It is even more advantageous when used on both sides.

  A particularly advantageous adhesive tape according to the invention is found to be an adhesive tape which is formed chemically and geometrically symmetrically, has an overall thickness of 200 μm and comprises a PET film of 12 μm thickness as support. (The thickness of each pressure-sensitive adhesive layer was 94 μm).

  Symmetrical adhesive tape offers the advantage of providing optimum shock absorption and stress compensation for the effects on each side. In particular, for applications where one or both disturbing effects can be expected to be completely or mainly from one side, the use of an asymmetric adhesive tape can also be advantageous, in this case pressure sensitive towards the disturbing side The adhesive layer here is preferably the thicker of both pressure sensitive adhesive layers in order to optimally compensate for disturbances. In this case, the overall thickness of the adhesive tape can be reduced by forming the pressure-sensitive adhesive layer on the opposite side, that is, on the side vulnerable to interference, as a thin layer. The opposite pressure-sensitive adhesive layer may be chemically identical to the thicker pressure-sensitive adhesive layer, but may be chemically different, particularly to suit the respective substrate to be applied.

  The double-sided adhesive tape according to the present invention is a temporary cover material on one or both sides, so that it is easier to handle, for example as a roll, in order to ensure a relatively long-term storage and comfortable handling during use. It is possible to provide a cover consisting of, preferably paper or a corresponding film, in particular paper or silicone film on both sides.

Finally, the present invention relates to a pressure sensitive adhesive for an adhesive tape comprising one support layer and two outer pressure sensitive adhesive layers, and the corresponding adhesive tape itself, wherein at least one of said pressure sensitive adhesives That is, the above-mentioned pressure sensitive adhesive is a cross-linked product, and this cross-linked product consists of a polymer composition comprising at least the following components: A) a polymer component (component A),
A polymer component comprising 88-100% by weight of at least one polyacrylate (component A1) consisting of a), b)
a) 1 to 15% by weight relative to component A1,
One or more monomers having at least one ethylenically unsaturated bond, each selected so that the glass transition temperature _TG of the corresponding homopolymer of each monomer is at least 0 ° C. (Monomer a),
However, at least a part of the monomer (a) further has at least one carboxylic acid group (monomer a1),
b) 85-99% by weight with respect to component A1,
One or more monomers from the group of acrylic esters and methacrylic esters, each selected so that the glass transition temperature _TG of the corresponding homopolymer comprising each monomer is -30 ° C or lower. Monomer (monomer b),
B) comprising a polymer composition comprising at least one crosslinker (component B) having two or more functional groups that are covalently crosslinked,
Component A and Component B together comprise at least 95% by weight of the polymer composition, and the loss factor tan δ (loss modulus G ″) of the pressure sensitive adhesive measured by DMA at 0.1 rad / s and 85 ° C. The ratio of storage modulus G ′) is in the range of 0.35 to 0.75, and the glass transition frequency f _G at 25 ° C. determined by DMA measurement is more than 5000 rad / s.

  In particular, this pressure sensitive adhesive exhibits excellent temperature resistance and is characterized by a slip distance of less than 1000 μm at 200 ° C. in the SAFT test (see below, chapter “Measurement”).

  The aforementioned pressure-sensitive adhesives having the characteristics of loss factor and glass transition frequency and preferably also the above-mentioned temperature resistance are in particular pressure-sensitive adhesives as further described in the frame of this description and in the claims. Therefore, it is preferred that the embodiments listed within the framework of this specification also apply to this pressure sensitive adhesive.

Use Finally, the present invention relates to the use of a polymer composition for producing a cross-linked pressure sensitive adhesive for a double-sided pressure sensitive adhesive tape of the type indicated in the frame of the present description, as well as plastic, glass or metal. In particular, it relates to the use of the double-sided pressure-sensitive adhesive tape according to the invention for attaching particularly transparent components, in particular windows (glass panels, polymer panels). The present invention relates in particular to such attachments for electronic, electrical and / or mechanical equipment, in particular electronic, electrical and / or mechanical terminal equipment or small equipment, Based on its size and weight, the device can be carried with little physical effort and is therefore mobile-friendly and is therefore provided specifically for carrying (so-called mobile devices) Or portable devices), eg, mobile phones, smartphones, and personal digital assistants (PDAs, eg, organizers, handhelds, palmtops), and even small computers (eg, laptops, notebooks, tablet PCs, mobile computers, pockets) Computer), gaming consoles, games Remote control device, sensor screen (touch screen), touch area (touch pad), operation unit for computers and electronic devices such as graphic tablets, wireless devices, GPS devices, navigation devices, portable interface devices for satellite communications Furthermore, electronic devices for playing electronic (entertainment) media such as Walkman and Discman, MP3 players, pocket TVs and pocket radios, E-book readers, digital cameras, film cameras, video cameras, watches, digital watches, Calculators, blood glucose measuring devices, blood pressure measuring devices, heart rate monitors, medical monitoring and / or control devices and / or monitors, medical mobile devices such as pedometers, tachometers and / or sports It is a medical mobile equipment for people. The above is not all.

Measurement method / Explanation regarding the above-mentioned parameter values I: Measurement using uncrosslinked polyacrylate (polymerization product) Average molecular weight The number average molar mass M _{N, P} and polydispersity PD data in this specification are: It relates to the determination of gel permeation chromatography (GPC). This determination is made on 100 μl of the clarified sample (sample concentration 4 g / l). Tetrahydrofuran containing 0.1% by volume of trifluoroacetic acid is used as the eluent. The measurement is performed at 25 ° C.

As a pre-column, column type PSS-SDV, 5 μm, 10 ^{3 ８} , 8.0 mm × 50 mm (herein and below the indication is type, particle size, porosity, inner diameter × length, 1 Å = 10 ^-10 m) is used. For the separation, use a combination of 8.0 mm × 300 mm columns of type PSS-SDV, 5 μm, 10 ³ Å and 10 ⁵ Å and 10 ⁶そ れ ぞ れ, respectively (according to Polymer Standards Service column, differential refractometer Shodex RI71) detection). The through-flow rate is 1.0 ml per minute. Calibration is performed against PMMA standards (polymethylmethacrylate calibration).

II. Measurement using resin Softening point _TE
Uses a ring and ball method to determine the softening point T _E of the resin, DIN EN 1427: performed by applying the decision 2007 accordingly (the resin sample instead of bitumen, but otherwise tested in intact process operations) . The measurement is performed in a glycerin bath. The data for the softening point relates to the result of this measurement.

III. Measurement using double-sided adhesive tape For the following tests, a symmetrical double-sided adhesive tape (overall thickness 200 μm, support film PET 12 μm) was used (see below for production).

Glass transition temperature T _G ; Glass transition frequency f _G ; Loss coefficient tan δ
The glass transition temperature T _G , the glass transition frequency f _G , and the loss factor tan δ were determined by dynamic mechanical analysis (DMA). At that time, the following process operations were selected. That is, the glass transition temperature was determined by a temperature sweep, the glass transition frequency was determined by a time-temperature superposition method (TTS), and the loss coefficient values (and loss elastic modulus values and storage elastic modulus values) were determined by frequency sweeping. All data within the framework of the present specification relate to the results of these measurements, unless otherwise indicated in individual cases.

  The DMA utilizes the fact that the characteristics of the viscoelastic material depend on the frequency (that is, time) and temperature of the load when a sinusoidal mechanical load is applied. In the TTS method, a frequency measurement performed at regular temperature intervals is processed into a frequency sweep, and thereby, it is possible to extend the frequency measurement by several tens of times below and above the range that can be obtained by measurement.

All DMA process operations Measuring equipment: Rheometric Scientific RDA III, measuring head: spring support with normal force, temperature control: heating chamber, measuring geometry: parallel plate configuration, sample thickness 1 (± 0.1) mm, Sample diameter 25 mm (5 layers of adhesive tape to be tested (each 200 μm) were laminated in order to make a 1 mm thick sample. PET support does not decisively contribute to rheological properties, so the presence of PET support Can be ignored.)

Temperature sweep Measurement frequency 10 rad / s, temperature range -40 ° C to + 130 ° C, heating rate 2.5 ° C / min, deformation 1%
Frequency sweep Measurement frequency 0.1 to 100 (512) rad / s, temperature 25 ° C., stress 2500 Pa, deformation 1%
TTS measurement Measurement frequency 0.1-512 rad / s, temperature is -35 to + 190 ° C at 15 ° C intervals, deformation 1%
Rolling Ball Tack The measurement of rolling ball tack is based on the PSTC-6 method (Test Methods for Pressure Sensitive Adhesive Tapes), 15th edition, published by Pressure Sensitive Tape Council, based on Northbrook, literature In doing so, the following changes were made.
-Ball of special steel ball bearing (special steel 1.4401), diameter 7 / 16Zoll (1.111cm), mass 5.7g
-Ball preparation: thorough washing with cellulose and acetone, clean balls stored in an acetone bath for 15 minutes before the series of measurements (the ball is completely surrounded by acetone), at least 30 minutes before the start of the measurement Removes the balls from the acetone bath and stores them barely in a standard atmosphere (23 ± 1 ° C., 50 ± 5% relative humidity) for drying and conditioning-each ball is used only for one measurement

  The initial adhesiveness was determined as follows. That is, a so-called “rolling ball tack” was measured as a measure of initial adhesion at a very short contact time. An approximately 30 cm long strip of adhesive tape was clamped with the adhesive side up and fixed horizontally on the test surface. For measurement, the steel ball was accelerated by rolling it down from a 65 mm high slope (tilt angle: 21 °) in the earth's gravitational field. Steel balls were guided directly from the ramp to the adhesive surface of the sample. The distance traveled before the ball stopped on the adhesive was measured. The temperature at the measurement place and the ball temperature at the time of measurement were 23 ± 1 ° C.

  The length of the rolling distance thus determined serves in this case as an inverse measure of the initial adhesiveness of the self-adhesive (ie, the shorter the rolling distance, the higher the initial adhesiveness and vice versa). Each measurement is an average of five individual measurements for each of the five different adhesive tape strips (as length data in mm).

Splitting test (FIG. 3 shows the stage of the test, and the position code of the part is used in the description of the preparation stage below)

Test material Steel angle made of SUS304 steel, acetone cleaning, steel surface 30 mm x 30 mm (3.2) and 30 mm x 60 mm (3.3), angle between the faces 90 °, larger surface (3.3) Hook hole (3.4)
・ Polycarbonate plate (PC plate) and polymethyl methacrylate plate (PMMA plate) (3.5), 75mm x 50mm each
・ Weight (3.7), 250g, with hook for hooking ・ Steel frame base (3.6)

Test preparation • The PC plate was stored at 85 ° C. for 24 hours and conditioned at room temperature for 30 minutes before application.
• PMMA plates were stored at 70 ° C. for 24 hours and conditioned for 30 minutes at room temperature before application.

  One side of the double-sided adhesive tape to be tested was adhered to release paper and cut into a 25 mm × 25 mm size sample (3.1). Adhere the uncovered adhesive surface of this square adhesive tape sample (3.1) to the middle of the outer surface of the smaller steel angle surface (3.2) respectively, then peel off the release paper and thus expose The glued surface was glued in the middle of the PC plate or PMMA plate (3.5), so the one with the larger steel angle (3.3) pointed vertically up. In order to generate a pressing force sufficient to attach both surfaces of each sample, a load was applied to the smaller horizontal steel angle surface (3.2) with a 6 kg weight for 10 minutes. Thereafter, the weight was removed, and the sample was left in this state for 24 hours at room temperature (adhesive training on each ground).

  Thereafter, the sample was air-conditioned at 85 ° C. for 10 minutes in a drying cabinet.

Test implementation (see Figure 3)
PC plate or PMMA plate (3.5) with steel angle (3.2, 3.3) attached with adhesive tape sample (3.1), steel angle (3.2, 3.3) facing down Place it on the steel frame base (3.6) so that it hangs (the larger surface (3.3) points vertically down). Next, the weight (3.7) (250 g) is hooked into the hole, thereby applying a load to the sticking portion, and this time is recorded as the start time.

  For each adhesive tape to be tested, 10 identical samples were prepared and subjected to 5 measurements on the PC plate and 5 measurements on the PMMA plate, respectively.

  The test is considered acceptable if the steel angle does not peel off after any of the 10 measurements after 72 hours.

Ball drop test In this test, data on the impact resistance ("Shock Resistance") of a sample sample affixed with the adhesive tape according to the present invention or a comparative sample can be taken. Derived from the shock absorption of the tape.

A square frame-shaped sample was cut out from the adhesive tape to be tested (outer dimension 33 mm × 33 mm, strand width 3.0 mm, inner dimension (“window”) 27 mm × 27 mm). This sample was bonded to an ABS frame (outer dimensions 50 mm × 50 mm, inner dimensions (“window”) 25 mm × 25 mm, thickness 3 mm). A 30 mm × 30 mm PMMA window was bonded to the other side of the double-sided adhesive tape. The ABS frame, the adhesive tape frame, and the PMMA window were pasted so that the geometric center and the diagonal line overlap each other (the corner is above the corner). The sticking surface was 360 mm ² . The affixing part was pressed at 10 bar for 5 seconds and left for 24 hours.

  An adhesive composite consisting of an ABS frame, adhesive tape and PMMA window is placed on the frame base with the protruding edge of the ABS frame so that the composite is aligned horizontally and the PMMA window hangs without hitting anywhere. And pointed down. A steel ball (diameter: 15 mm, mass: 5.6 g) was dropped vertically from a height of 250 cm on the sample thus arranged (measurement condition: 23 ° C., relative humidity: 50%). Three tests were performed on each sample.

  The ball drop test is considered acceptable if the sticking does not peel off in any of the three tests.

SAFT—Shear Bond Failure Temperature This test is useful for rapid inspection of the adhesive tape shear strength under temperature loading. In this regard, the adhesive tape to be tested is glued onto a temperature-adjustable steel plate, loaded with a weight (50 g) and the shear distance is recorded.

Preparation of measurement sample Adhesive tape to be tested is bonded onto a 50 μm thick aluminum film. The adhesive tape thus prepared is cut into a size of 10 mm × 50 mm.

  On the steel inspection plate (material 1.4301, DIN EN 10088-2, surface 2R, surface roughness Ra = 30 to 60 nm, dimensions 50 mm × 13 mm × 1.5 mm), which was obtained by polishing the cut adhesive tape sample and washing it with acetone Further, the sample is attached so that the surface of the sample becomes height × width = 13 mm × 10 mm and the upper edge of the steel inspection plate protrudes 2 mm. Next, for fixing, the 2 kg steel roller is rotated 6 times at a speed of 10 m / min. The sample is precisely reinforced on the upper side with a stable adhesive strip, which serves as a support for the distance measuring sensor. The sample is then suspended by the steel plate so that the longer protruding end of the adhesive tape points vertically downward.

Measurement At the lower end of the sample to be measured, load with a 50 g weight. The steel test plate with the sample attached is heated to a final temperature of 200 ° C. at a rate of 9 ° C. per minute starting from 25 ° C.

  The distance measurement sensor observes the sliding distance of the sample according to temperature and time. The maximum sliding distance is defined as 1000 μm (1 mm), and the test is interrupted if exceeded. The inspection atmosphere is a room temperature of 23 ± 3 ° C. and a relative humidity of 50 ± 5%.

  In the test, a case where the sliding distance at 200 ° C. does not exceed the value of 1000 μm is regarded as acceptable (assuming that the sample is sufficiently temperature resistant). If the test fails, the temperature when the maximum slip distance (1000 μm) is reached is displayed (unit: ° C.).

Experimental Part Pressure Sensitive Adhesive Production A conventional 2L glass reactor suitable for radical polymerization under boiling cooling was added to a monomer mixture 300 g containing 142.5 g butyl acrylate, 142.5 g ethylhexyl acrylate and 15 g acrylic acid and acetone. : 200 g of benzene (1: 1) having a boiling range of 60/95 was charged. After passing nitrogen gas for 45 minutes with stirring, the reactor was heated to 58 ° C. and 0.15 g of 2,2′-azodi (2-methylbutyronitrile) (Vazo67®, DuPont) was added. It was dissolved in 6 g of acetone and added. Subsequently, the outside heating tank was heated to 75 ° C., and the reaction was carried out at a constant outside temperature. After a reaction time of 1 hour, 0.15 g of VAZO 67® was again dissolved in 6 g of acetone and added. After 3 hours, the mixture was diluted with 90 g of acetone: benzine (1: 1) having a boiling range of 60/95.

After a reaction time of 5 and a half hours, 0.45 g of bis- (4-tert.-butylcyclohexanyl) -peroxydicarbonate (Perkadox 16®, Akzo Nobel) was dissolved in 9 g of acetone and added. It was. After a reaction time of 7 hours, an additional 0.45 g of bis- (4-tert.-butylcyclohexanyl) -peroxydicarbonate (Perkadox 16®, Akzo Nobel) was dissolved in 9 g of acetone and added. It was. After a reaction time of 10 hours, the mixture was diluted with 90 g of acetone: benzine (1: 1) having a boiling range of 60/95. The reaction was interrupted after 24 hours reaction time and cooled to room temperature. The number average molecular weight of the resulting polymer was in the range of M _n = 100,000 g / mol for all polymers thus produced (see table).

  The polymer is then treated with a suitable amount of a crosslinker [Examples 1-15 are 3% tetraglycidylmethyxylenediamine in acetone; Erisys® GA-240 solution, Example 16 is 3% aluminum in acetone. -(III) -acetylacetonate solution] with respect to the resin mixed adhesive, a suitable amount of adhesive resin (Sylvares TP95®, terpene phenol resin, softening temperature 92-98 ° C. (typical of manufacturer announcement) The value was 95 ° C., Arizona Chemical)) and diluted with acetone: benzine (1: 1) with a boiling range of 60/95 to a solids content of 40%.

  Refer to the data in Table 1 for the amount of cross-linking agent and resin. The data for parts by weight of crosslinker are based on 100 parts by weight of polyacrylate component A1, respectively, with respect to the amount of pure crosslinker (no diluent).

Preparation of double-sided pressure-sensitive adhesive tape composite A 40% polymer composition solution was coated on a liner material (silicone-treated release paper) and dried for 15 minutes at 120 ° C, during which a crosslinking reaction occurred. After drying, a 94 μm thick crosslinked pressure sensitive adhesive layer was obtained.

  The pressure-sensitive adhesive layer thus produced was laminated on both sides of a PET support film having a thickness of 12 μm by an ordinary method, whereby a symmetric double-sided pressure-sensitive adhesive tape having an overall thickness of 200 μm was obtained.

  The results of the experiment are shown in Table 1.

  The suitability of this pressure sensitive adhesive for the required field of use is demonstrated by passing the split and ball drop tests. For this, it is necessary to adjust the rheological properties of the pressure sensitive adhesive very accurately. This is done according to the present invention by the amount and type of polymer used, the amount of cross-linking agent used, and the limitation of mixing of the adhesive resin. Fine tuning can be further optimized by selecting an excellent cross-linking agent as shown within the framework of this specification.

  Optionally, a resin can be mixed into the pressure sensitive adhesive. However, too much resin mixing (more than 13% by weight here) failed the ball drop test, that is, the pressure sensitive adhesive was found to be unsuitable for the intended use (Examples 3, 5). , 7, 8, 12).

  A pass of the split test indicates the resistance of the tested adhesive tape and the adhesive produced thereby, particularly against low frequency interference. In particular, the split test serves to explain the suitability of bending stress compensation and excellent temperature aggregation persistence.

The main claim is that the amount ratio V = n _Z / n _P between the substance amount n _Z of the crosslinking active center of the crosslinking agent and the theoretical substance quantity n _P of the macromolecule of the polymer component A1 passes the split test. It was confirmed that the selection was made within a specific range as shown in (see Examples 1, 2, 3, 7, 10, 11, 12). The degree of cross-linking achieved by the amount of these cross-linking agents can be particularly well characterized by the loss factor tan δ. For successful examples, the loss factor is within the range set within the framework of this specification.

  The ball drop test is particularly suitable for examining the impact absorbing power of the adhesive tape, ie its suitability for mitigating mechanical effects such as drop or impact. If you pass this test, your aptitude for this is considered sufficient.

From the experiments, it can be seen that the ball drop test was always passed when the rolling ball tack test had a value of 50 mm or less. As a further feature, the glass transition frequency f _G at 25 ° C. can be taken up. The ball drop test passed with samples where the glass transition frequency f _G at 25 ° C. reached a value of at least 5000 rad / s (Examples 1, 2, 4, 6, 9, 10, 11, 13, 14).

  The adhesive tape having the characteristics according to the invention passes the temperature resistance test (SAFT test) in the same way as an adhesive tape with a highly crosslinked pressure sensitive adhesive. However, insufficient crosslinking of the polyacrylate component (too little amount of crosslinking agent) results in insufficient temperature resistance.

  In addition, the sample cross-linked with the aluminum chelate cross-linking agent (Example 16) passes the ball drop test but does not pass the splitting test and does not exhibit excellent temperature resistance (SAFT test failure). It could be confirmed. Therefore, the pressure-sensitive adhesive thus crosslinked does not satisfy the requirements based on the problem. That is, the pressure sensitive adhesive produced using the crosslinker required by the present invention has clear advantages over the chelate crosslinked pressure sensitive adhesive.

  Thus, it has been found that the claimed adhesive tape is particularly well suited to fulfilling the objective task. Similarly, the claimed polymer composition is particularly suitable for producing such adhesive tapes.

This application is directed to the claimed invention, but the disclosure of this application also includes:
1.
  A double-sided adhesive tape comprising one support layer and two outer pressure sensitive adhesive layers,
  In this case, at least one of the pressure sensitive adhesives is a cross-linked product, and the cross-linked product consists of a polymer composition containing at least the following components:
A) polymer component (component A),
  A polymer component comprising 88-100% by weight of at least one polyacrylate (component A1) consisting of a), b)
  a) 1 to 15% by weight relative to component A1,
  One or more monomers having at least one ethylenically unsaturated bond, each having a glass transition temperature T of the corresponding homopolymer comprising each monomer _G Monomer selected to be at least 0 ° C. (monomer a),
  In this case, at least a part of the monomer (a) further has at least one carboxylic acid group (monomer a1),
  b) 85-99% by weight with respect to component A1,
  One or more monomers from the group of acrylic esters and methacrylic esters, each having a glass transition temperature T of the corresponding homopolymer consisting of each monomer _G A monomer (monomer b) selected so that is less than −30 ° C.,
B) consisting of a polymer composition comprising at least one difunctional or polyfunctional crosslinker (component B) that is covalently crosslinked,
  In an adhesive tape where component A and component B together comprise at least 95% by weight of the polymer composition,
  The amount n of the crosslinking active center of the crosslinking agent is at least one kind of crosslinking agent _Z And the theoretical amount of macromolecule n of polymer component A1 _P Ratio of V to n _Z / N _P Is present in an amount showing a value between 0.15 and 0.60,
  Substance amount n of crosslinking active center of crosslinking agent _Z Is the mass m of the crosslinking agent multiplied by the number f of crosslinking active centers per molecule of the crosslinking agent _V Is the molar mass M of the cross-linking agent _V Divided by, i.e. n _Z = F · m _V / M _V And
  Theoretical mass n of macromolecule of polymer component A1 _P Is the mass m of the polymer component in the pressure sensitive adhesive _P The number average molar mass M of the ingredients _{n, P} Divided by, i.e. n _P = M _P / M _{n, P} The adhesive tape characterized by being.

2.
  An adhesive tape comprising one support layer and two outer pressure-sensitive adhesive layers, in particular the adhesive tape of claim 1,
  In this case, at least one of the pressure sensitive adhesives is a cross-linked product, and the cross-linked product consists of a polymer composition containing at least the following components:
A) polymer component (component A),
  A polymer component comprising 88-100% by weight of at least one polyacrylate (component A1) consisting of a), b)
  a) 1 to 15% by weight relative to component A1,
  One or more monomers having at least one ethylenically unsaturated bond, each having a glass transition temperature T of the corresponding homopolymer comprising each monomer _G Monomer selected to be at least 0 ° C. (monomer a),
  In this case, at least a part of the monomer (a) further has at least one carboxylic acid group (monomer a1),
  b) 85-99% by weight with respect to component A1,
  One or more monomers from the group of acrylic esters and methacrylic esters, each having a glass transition temperature T of the corresponding homopolymer consisting of each monomer _G A monomer (monomer b) selected so that is less than −30 ° C.,
B) consisting of a polymer composition comprising at least one difunctional or polyfunctional crosslinker (component B) that is covalently crosslinked,
  In an adhesive tape where component A and component B together comprise at least 95% by weight of the polymer composition,
  The loss factor tan δ (ratio of loss modulus G ″ to storage modulus G ′) of the pressure sensitive adhesive measured by DMA at 0.1 rad / s and 85 ° C. is in the range of 0.35 to 0.75. Yes,
  Glass transition frequency f at 25 ° C. determined by DMA measurement _G Is an adhesive tape characterized by having a viscosity of more than 5000 rad / s.

3.
  3. The adhesive tape as described in 1 or 2 above, wherein the monomer a1 is present in an amount of 3 to 5% by weight based on the component A1.

4).
  Any one of the above 1 to 3, wherein at least a part of the monomer is selected from the group comprising methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate (monomer a2) The adhesive tape as described in one.

5.
  6. The adhesive tape as described in 4 above, wherein the monomer a2 is present at a maximum of 10% by weight based on the component A1.

6).
  6. The polymer component A further comprises a resin component (component A2) having a softening point of 80 to 150 ° C. at a maximum of 12% by weight, preferably a maximum of 10% by weight. Adhesive tape.

7).
  The adhesive tape according to any one of 1 to 6, wherein the crosslinking agent is a crosslinking agent that reacts covalently.

8).
  7. The adhesive tape as described in 6 above, wherein a compound containing both an epoxy functional group and an amine functional group in the molecule is used as the crosslinking agent.

9.
  The adhesive tape according to any one of 1 to 8, wherein tetraglycidylmetaxylenediamine is used as a crosslinking agent.

10.
  Substance amount n of crosslinking active center of crosslinking agent _Z And the theoretical amount of macromolecule n of polymer component A1 _P Ratio of V to n _Z / N _P The adhesive tape according to any one of 1 to 9 above, wherein a value of between 0.38 and 0.59 is exhibited.

11.
  11. The adhesive tape according to any one of 1 to 10 above, which has a thickness of 100 to 300 [mu] m.

12
  12. The adhesive tape according to any one of 1 to 11, wherein the pressure-sensitive adhesive layers on both sides of the support layer are geometrically the same.

13.
  13. The adhesive tape as described in any one of 1 to 12 above, wherein the pressure-sensitive adhesive on both sides of the support layer is chemically the same.

14
  A polymer composition comprising at least the following components for producing a cross-linked pressure sensitive adhesive for an adhesive tape, in particular for an adhesive tape according to any one of the above 1-13:
A) polymer component (component A),
  A polymer component comprising 88-100% by weight of at least one polyacrylate (component A1) consisting of a), b)
  a) 1 to 15% by weight relative to component A1,
  One or more monomers having at least one ethylenically unsaturated bond, each having a glass transition temperature T of the corresponding homopolymer comprising each monomer _G Monomer selected to be at least 0 ° C. (monomer a),
  In this case, at least a part of the monomer (a) further has at least one carboxylic acid group (monomer a1),
  b) 85 to 99% by weight relative to component (A1),
  One or more monomers from the group of acrylic esters and methacrylic esters, each having a glass transition temperature T of the corresponding homopolymer consisting of each monomer _G A monomer (monomer b) selected so that is less than −30 ° C.,
B) a polymer composition comprising at least one difunctional or polyfunctional crosslinking agent (component B),
  The amount n of the crosslinking active center of the crosslinking agent is at least one kind of crosslinking agent _Z And the theoretical amount of macromolecule n of polymer component A1 _P Ratio of V to n _Z / N _P Is present in an amount showing a value between 0.15 and 0.6,
  Substance amount n of crosslinking active center of crosslinking agent _Z Is the mass m of the crosslinking agent multiplied by the number f of crosslinking active centers per molecule of the crosslinking agent _V Is the molar mass M of the cross-linking agent _V Divided by, i.e. n _Z = F · m _V / M _V And
  Theoretical mass n of macromolecule of polymer component A1 _P Is the mass m of the polymer component in the pressure sensitive adhesive _P The number average molar mass M of this component _{n, P} Divided by, i.e. n _P = M _P / M _{n, P} A polymer composition.

Claims (17)

A double-sided adhesive tape comprising one support layer and two outer pressure sensitive adhesive layers,
At least one of the pressure sensitive adhesives is a cross-linked product, and the cross-linked product consists of a polymer composition containing at least the following components: A) a polymer component (component A),
A polymer component comprising 88-100% by weight of at least one polyacrylate (component A1) consisting of a), b)
a) 1 to 15% by weight relative to component A1,
One or more monomers having at least one ethylenically unsaturated bond, each selected so that the glass transition temperature _TG of the corresponding homopolymer of each monomer is at least 0 ° C. (Monomer a),
However, at least a part of the monomer (a) further has at least one carboxylic acid group (monomer a1),
b) 85-99% by weight with respect to component A1,
One or more monomers from the group of acrylic esters and methacrylic esters, each selected so that the glass transition temperature _TG of the corresponding homopolymer comprising each monomer is -30 ° C or lower. Monomer (monomer b),
B) consisting of a polymer composition comprising at least one crosslinking agent (component B) having two or more functional groups that are covalently crosslinked,
In an adhesive tape where component A and component B together comprise at least 95% by weight of the polymer composition,
The at least one crosslinking agent is such that the amount ratio V = n _Z / n _{P of the} amount n _Z of the crosslinking active center of the crosslinking agent and the theoretical amount n _P of the macromolecule of the polymer component A1 is 0.15. Present in an amount indicating a value between ˜0.60,
Amount of substance n _Z of the crosslinking active centers of the crosslinker is sought by dividing the cross-linking agent mass m _V obtained by multiplying the number f of the crosslinking active centers per crosslinker molecule with the molar mass M _V of the crosslinker, i.e. n It is _{Z = f · m V / M} V,
Amount of substance n _P theoretical macromolecular polymer component A1 is a number-average molar mass M _n of the mass m _P of the polymer component in the pressure-sensitive adhesive the _components are calculated by dividing by _P, that n _P = M _P / M _{n, P.} Adhesive tape characterized by the above-mentioned. An adhesive tape comprising one support layer and two outer pressure sensitive adhesive layers,
At least one of the pressure sensitive adhesives is a cross-linked product, and the cross-linked product consists of a polymer composition containing at least the following components: A) a polymer component (component A),
A polymer component comprising 88-100% by weight of at least one polyacrylate (component A1) consisting of a), b)
a) 1 to 15% by weight relative to component A1,
One or more monomers having at least one ethylenically unsaturated bond, each selected so that the glass transition temperature _TG of the corresponding homopolymer of each monomer is at least 0 ° C. (Monomer a),
However, at least a part of the monomer (a) further has at least one carboxylic acid group (monomer a1),
b) 85-99% by weight with respect to component A1,
One or more monomers from the group of acrylic esters and methacrylic esters, each selected so that the glass transition temperature _TG of the corresponding homopolymer comprising each monomer is -30 ° C or lower. Monomer (monomer b),
B) consisting of a polymer composition comprising at least one crosslinking agent (component B) having two or more functional groups that are covalently crosslinked,
In an adhesive tape where component A and component B together comprise at least 95% by weight of the polymer composition,
The loss factor tan δ (ratio of loss modulus G ″ to storage modulus G ′) of the pressure sensitive adhesive measured by DMA at 0.1 rad / s and 85 ° C. is in the range of 0.35 to 0.75. Yes,
An adhesive tape having a glass transition frequency f _G at 25 ° C. determined by DMA measurement of more than 5000 rad / s. The adhesive tape of claim 1 comprising one support layer and two outer pressure sensitive adhesive layers,
At least one of the pressure sensitive adhesives is a cross-linked product, and the cross-linked product consists of a polymer composition containing at least the following components: A) a polymer component (component A),
A polymer component comprising 88-100% by weight of at least one polyacrylate (component A1) consisting of a), b)
a) 1 to 15% by weight relative to component A1,
One or more monomers having at least one ethylenically unsaturated bond, each selected so that the glass transition temperature _TG of the corresponding homopolymer of each monomer is at least 0 ° C. (Monomer a),
However, at least a part of the monomer (a) further has at least one carboxylic acid group (monomer a1),
b) 85-99% by weight with respect to component A1,
One or more monomers from the group of acrylic esters and methacrylic esters, each selected so that the glass transition temperature _TG of the corresponding homopolymer comprising each monomer is -30 ° C or lower. Monomer (monomer b),
B) consisting of a polymer composition comprising at least one crosslinking agent (component B) having two or more functional groups that are covalently crosslinked,
In an adhesive tape where component A and component B together comprise at least 95% by weight of the polymer composition,
The loss factor tan δ (ratio of loss modulus G ″ to storage modulus G ′) of the pressure sensitive adhesive measured by DMA at 0.1 rad / s and 85 ° C. is in the range of 0.35 to 0.75. Yes,
An adhesive tape having a glass transition frequency f _G at 25 ° C. determined by DMA measurement of more than 5000 rad / s.   The adhesive tape according to any one of claims 1 to 3, wherein the monomer a1 is present in an amount of 3 to 5% by weight based on the component A1.   5. The monomer according to claim 1, wherein at least a part of the monomer is selected from the group comprising acrylic acid methyl ester, acrylic acid ethyl ester, methacrylic acid methyl ester, and methacrylic acid ethyl ester (monomer a2). The adhesive tape as described in any one.   6. Adhesive tape according to claim 5, characterized in that the monomer a2 is present in a maximum of 10% by weight with respect to component A1.   The adhesive tape according to any one of claims 1 to 6, wherein the polymer component A further contains a resin component (component A2) having a softening point of 80 to 150 ° C at a maximum of 12% by weight.   The adhesive tape according to claim 1, wherein the crosslinking agent is a crosslinking agent that reacts covalently.   The adhesive tape according to claim 7, wherein a compound containing both an epoxy functional group and an amine functional group in the molecule is used as the crosslinking agent.   The adhesive tape according to any one of claims 1 to 9, wherein tetraglycidylmetaxylenediamine is used as a crosslinking agent. The amount ratio V = n _Z / n _P between the amount n _Z of the crosslinking active center of the crosslinking agent and the theoretical amount n _P of the macromolecule of the polymer component A1 is between 0.38 and 0.59. The adhesive tape according to claim 1, wherein the adhesive tape is shown.   The adhesive tape according to claim 1, which has a thickness of 100 to 300 μm.   The adhesive tape according to claim 1, wherein the pressure-sensitive adhesive layers on both sides of the support layer are formed with the same thickness.   The adhesive tape according to claim 1, wherein the pressure-sensitive adhesive on both sides of the support layer is chemically the same. The adhesive tape as described in any one of Claims 1-14 for affixing glass or a transparent plastic in a household electronic device product. A polymer composition comprising at least the following components for producing a crosslinked pressure sensitive adhesive: A) a polymer component (component A),
A polymer component comprising 88-100% by weight of at least one polyacrylate (component A1) consisting of a), b)
a) 1 to 15% by weight relative to component A1,
One or more monomers having at least one ethylenically unsaturated bond, each selected so that the glass transition temperature _TG of the corresponding homopolymer of each monomer is at least 0 ° C. (Monomer a),
However, at least a part of the monomer (a) further has at least one carboxylic acid group (monomer a1),
b) 85 to 99% by weight relative to component (A1),
One or more monomers from the group of acrylic esters and methacrylic esters, each selected so that the glass transition temperature _TG of the corresponding homopolymer comprising each monomer is -30 ° C or lower. Monomer (monomer b),
B) a polymer composition comprising at least one crosslinking agent (component B) having two or more functional groups,
The at least one crosslinking agent is such that the amount ratio V = n _Z / n _{P of the} amount n _Z of the crosslinking active center of the crosslinking agent and the theoretical amount n _P of the macromolecule of the polymer component A1 is 0.15. Present in an amount indicating a value between ~ 0.6,
Amount of substance n _Z of the crosslinking active centers of the crosslinker is sought by dividing the cross-linking agent mass m _V obtained by multiplying the number f of the crosslinking active centers per crosslinker molecule with the molar mass M _V of the crosslinker, i.e. n It is _{Z = f · m V / M} V,
Amount of substance n _P theoretical macromolecular polymer component A1 is a number-average molar mass M _n of component mass m _P of the polymer component in the pressure-sensitive _adhesive, is calculated by dividing by _P, that n _P = Polymer composition _where m _P / M _{n, P.} A polymer composition comprising at least the following components for producing a crosslinked pressure-sensitive adhesive for an adhesive tape according to any one of claims 1-15 : A) a polymer component (component A),
A polymer component comprising 88-100% by weight of at least one polyacrylate (component A1) consisting of a), b)
a) 1 to 15% by weight relative to component A1,
One or more monomers having at least one ethylenically unsaturated bond, each selected so that the glass transition temperature _TG of the corresponding homopolymer of each monomer is at least 0 ° C. (Monomer a),
However, at least a part of the monomer (a) further has at least one carboxylic acid group (monomer a1),
b) 85 to 99% by weight relative to component (A1),
One or more monomers from the group of acrylic esters and methacrylic esters, each selected so that the glass transition temperature _TG of the corresponding homopolymer comprising each monomer is -30 ° C or lower. Monomer (monomer b),
B) a polymer composition comprising at least one crosslinking agent (component B) having two or more functional groups,
The at least one crosslinking agent is such that the amount ratio V = n _Z / n _{P of the} amount n _Z of the crosslinking active center of the crosslinking agent and the theoretical amount n _P of the macromolecule of the polymer component A1 is 0.15. Present in an amount indicating a value between ~ 0.6,
Amount of substance n _Z of the crosslinking active centers of the crosslinker is sought by dividing the cross-linking agent mass m _V obtained by multiplying the number f of the crosslinking active centers per crosslinker molecule with the molar mass M _V of the crosslinker, i.e. n It is _{Z = f · m V / M} V,
Amount of substance n _P theoretical macromolecular polymer component A1 is a number-average molar mass M _n of component mass m _P of the polymer component in the pressure-sensitive _adhesive, is calculated by dividing by _P, that n _P = Polymer composition _where m _P / M _{n, P.}

Images